The InSight lander has been on the surface of Mars for about a year, and a half dozen papers were just published outlining some results from the mission. Though InSight’s primary mission is to gather evidence on the interior of Mars—InSight stands for Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport—the lander also keeps track of Martian Meteorology. A new paper reports that InSight has found gravity waves, swirling dust devils, and a steady background rumble of infrasound.
An atmospheric drama has been playing out on Mars lately. Up until now, the main actor has been methane, and its unusual, spiking behaviour. But now Oxygen is taking the stage, and performing some theatrics of its own.
During winter in the polar regions, a thin layer of carbon dioxide ice covers the surface and then sublimates – turns directly from ice into vapour – with the first light of spring. In the dune fields, this springtime defrosting occurs from the bottom up, trapping gas between the ice and the sand. As the ice cracks, this gas is released violently and carries sand with it, forming the dark patches and streaks observed in this CaSSIS image. ESA/Roscosmos/CaSSIS, CC BY-SA 3.0 IGO
Springtime on Earth can be a riotous affair, as plants come back to life and creatures large and small get ready to mate. Nothing like that happens on Mars, of course. But even on a cold world like Mars, springtime brings changes, though you have to look a little more closely to see them.
Lucky for us, there are spacecraft orbiting Mars with high-resolution cameras, and we can track the onset of Martian springtime through images.
It’s easy to take for granted the detailed, almost real-time knowledge of Mars that we have at our fingertips. After all, in the not-too-distant past, Mars was largely mysterious. All we had were ground-based images of the planet. Now? Now we have daily weather reports and images of dust storms.
This image illustrates possible ways methane might get into Mars’ atmosphere and also be removed from it: microbes (left) under the surface that release the gas into the atmosphere, weathering of rock (right) and stored methane ice called a clathrate. Ultraviolet light can work on surface materials to produce methane as well as break it apart into other molecules (formaldehyde and methanol) to produce carbon dioxide. Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan
For centuries, scientists have speculated about the existence of life on Mars. But it was only within the past 15 years that the search for life (past and present) really began to heat up. It was at this time that methane, an organic molecule that is associated with many forms of life here on Earth (i.e. a “biosignature”) was detected in Mars’ atmosphere.
Since that time, attempts to study Mars’ atmospheric methane have produced varying results. In some cases, methane has been found that was several times its normal concentrations; in others, it was absent. Seeking to answer this mystery, an interdisciplinary team from Aarhus Universityrecently conducted a study where they investigated a possible mechanism for the removal of methane from Mars’ atmosphere.
Mars, as it was observed shortly before opposition in 2016 by the NASA/ESA Hubble Space Telescope. Credit: NASA/ESA/HST
On Earth, clouds form when enough droplets of water condense out of the air. And those droplets require a tiny speck of dust or sea salt, called a condensation nuclei, to form. In Earth’s atmosphere, those tiny specks of dust are lofted high into the atmosphere where they trigger cloud formation. But on Mars?
Comparison images of Mars taken by Hubble (left) and showing a global dust storm that engulfed it (right). Astronomers studying dust storms in the Aonia-Solis-Valles Marineris region over eight years have found a distinct periodicity in their occurrence. Image Credit: NASA
To say there are some myths circulating about Martian dust storms would be an understatement. Mars is known for its globe-encircling dust storms, the likes of which are seen nowhere else. Science fiction writers and Hollywood movies often make the dust storms out to be more dangerous than they really are. In “The Martian,” a powerful dust storm destroys equipment, strands Matt Damon on Mars, and forces him into a brutal struggle for survival.
Mars in 2001. On the left, no global dust storm. On the right, global dust storm. Image Credit: By Jim Secosky picked out this NASA image NASA/JPL/MSSS - https://photojournal.jpl.nasa.gov/figures/PIA03170_fig1.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=65809875
The enduring, and maybe endearing, mystery around Mars is what happened to its water? We can say with near-certainty now, thanks to the squad of Mars rovers and orbiters, that Mars was once much wetter. In fact that planet may have had an ocean that covered a third of the surface. But what happened to it all?
As it turns out, the global dust storms that envelop Mars, and in particular the most recent one that felled the Opportunity rover, may offer an explanation.
A photo of a preserved river channel on Mars. The color is overlaid to show elevation, with blue being low and yellow being high elevation. Image Credit: NASA/JPL/Univ. Arizona/UChicago
The ancient climate of Mars is a mystery to scientists. Even with all we’ve learned about Mars, it’s still difficult to explain how lakes and rivers existed. A new study shows that Martian rivers were swollen with runoff and that they flowed far later into the planet’s history than previously thought.
The question is, how did the Martian climate create these conditions?
On October 19th, 2016, the European Space Agency’s Exobiology on Mars (ExoMars) mission established orbit around Mars. Consisting of the ExoMars Trace Gas Orbiter (TGO) and the Schiaparelli lander, the purpose of this mission is to investigate Mars for past signs of life. And whereas the Schiaparelli unfortunately crashed during deployment, the TGO has managed to begin its mission ahead of schedule.
A few weeks ago, the satellite achieved a near circular orbit around Mars after performing a series of braking maneuvers. Since that time, the orbiter’s Color and Stereo Surface Imaging System (CaSSIS) took a stunning image of the surface. This picture was not only the TGO’s first image of Mars, it was also a test to see if the orbiter is ready to being its main mission on April 28th.
The image captured a 40 km- (25 mi) long segment of the Korolev Crater, which is located high in Mars’ northern hemisphere. The image was a composite of three images in different colors that were taken simultaneously on April 15th, 2018, which were then assembled to produce this color image. The bright material that appears at the edge of the crater is water ice.
The ExoMars Colour and Stereo Surface Imaging System, CaSSIS, captured this view of the rim of Korolev crater (73.3ºN/165.9ºE). Copyright ESA/Roscosmos/CaSSIS
As Antoine Pommerol, a member of the CaSSIS science team working on the calibration of the data, explained in a recent ESA press release:
“We were really pleased to see how good this picture was given the lighting conditions. It shows that CaSSIS can make a major contribution to studies of the carbon dioxide and water cycles on Mars.”
Prior to the test phase, the camera team transmitted new software to the TGO, and after a few minor issues, they determined that the instrument was ready to work. The camera is one of four instruments on the TGO, which also carries two spectrometer suites and a neutron detector. The spectrometers began their science mission on April 21st by taking the first sample of the atmosphere to see how its molecules absorb sunlight.
By doing this, the TGO hopes to determine the chemical composition of Mars atmosphere and find evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes. Eventually, the camera will help characterize features on the surface that could be related to trace gas sources. Hence the importance of this recent test.
ExoMars’ Trace Gas Orbiter (TGO) and Schiaparelli lander seperating in orbit of Mars. Credit: ESA/ATG medialab
“We aim to fully automate the image production process,” said Nicolas Thomas, the camera’s principal investigator from the University of Bern. “Once we achieve this, we can distribute the data quickly to the science community for analysis.”
A lot of challenges lie ahead, which includes a long period of data collection to bring out the details of rare (or yet to be discovered) trace gases in Mars’ atmosphere. This is necessary since trace gases (as the name would suggest) are present in only very small amounts – i.e. less than 1% of the volume of the planet’s atmosphere. But as Håkan Svedhem – the ESA’s TGO project scientist – indicated, the test image was a good start.
“We are excited to finally be starting collecting data at Mars with this phenomenal spacecraft,” he said. “The test images we have seen so far certainly set the bar high.”
By 2020, the second part of the ExoMars mission is scheduled to launch. This will consist of a Russian surface platform and a European rover landing on the surface in support of a science mission that is expected to last into 2022 or longer. Alongside NASA’s proposed Mars 2020 rover, the Red Planet is due to have several more visitors in the coming years!
